interstitial lung disease

Question 1

interstitial lung disease definition

Answer 1

Lung parenchymal disorders with common clinical, radiologic, physiologic and pathologic features, INVOLVEMENT OF THE INTERSTITIUM is the hallmark

Synonymous with:
Infiltrative lung disease: infiltration of cellular and non cellular elements within alveolar septa and alveoli
Diffuse parenchymal lung disease, diffuse interstitial lung disease, restrictive lung disease (reduced total lung capacity in presence of normal or reduced expiratory flow rate

Question 2

pathogenesis

Answer 2

alveolitis: damage to pneumocytes and endothelial cells, leads to leukocytes releasing cytokines which mediate and stimulate interstitial fibrosis

Interstitial fibrosis: decreased lung compliance and elasticity, decreased lung expansion during inspiration

Question 3

Interstitial lung disease clinical and lab findings

Answer 3

Dry cough and dyspnea, late inspiratory crackles, bibasilar (Velcro crackles) Cor pulmonale, CXR: bilateral reticulonodular infiltrates

Question 4

Types of interstital lung disease

Answer 4

Acute interstitial lung disease: Acute lung injury (ALI/ARDS)
Chronic interstitial lung disease: 
Fibrosing lung disorders: Usual interstitial pneumonia (idiopathic pulmonary fibrosis), pneumonia, collagen vascular diseases, pneumoconiosis
Granulomatous disorders (Sarcoidosis, hypersensitivity pneumonitis), eosinophilic, smoking related, others

Occupational and Environmental inhalants

Question 5

Pneumoconioses

Answer 5

non-neoplastic lung diseases in response to inhalation of mineral dusts

Now expanded to include diseases induced by organic and inorganic particulate matter/chemical fumes/vapors (hypersensitivity, pneumonitis), minerals: coal dust, silica, asbestos, beryllium

25% cases of chronic intersitial lung disease

The development of pneumoconioses depends on: the amount of dust retained in the lung parenchyma and airways, the size shape and buoyancy of particles : 1-5 um reach bifurcation of respiratory bronchioles and alveolar ducts,

Question 6

Fibrogenic pneumoconioses

Answer 6

Coal workers’ pneumoconiosis (carbon dust), silicosis (cyrstalline silica), silicatosis (talc, kaolin, feldsap, mica, muscovite), asbestosis (asbestos fibers), rare forms (metalloconiosis berylliosis, hard metal lung disease, aluminosis), thesaouriosis hairspray

Question 7

nonfibrogenic pneumoconioses

Answer 7

siderosis (iron oxide), baritosis (barium sulfate or bartyes), stannosis (tin dioxide or cassiterite), zirconium lung disease, antimoney lung disease

Question 8

Coal workers pneumoconiosis

Answer 8

Anthracotic (carbon) pigment)- coal mines, urban centers, tobacco smoke

Pulmonary anthracosis: pigment in intersitial compartment and lymph nodes, asymptomatic

Simple CWP, complicated CWP Progressive massive fibrosis, small fibrous opacities, upper lobes,

complicated, progressive, large opacities, with or withour central necrosis, massive fibrosis, caplan syndrome, no increase incidence of TB or cancer

Question 9

Silicosis pneumoconioses

Answer 9

Most common occupational disease worldwide

Crystalline silicon dioxide (quartz), foundries, sandblasting, silica mines

Quartz activates alveolar macrophages after engulfment–>cytokine release–>fibrogenesis

Silicosis (chronic exposure) nodular opacities with concentric layers of collagen, polarizable quartz particles can be seen, egg shell calcification in hilar lymph nodes

Complications: cor pilmonale, Caplan syndrome, Increased risk of TB and cancer

Question 10

ASbestos forms

Answer 10

Serpentine curly and flexible, amphibole staraight and rigid
Deposition sites: respiratory bronchioles, alveolar ducts, alveoli

Sources: insulation, roofing demolition of old buildings

Tissue appearance: ferruginous bodies: macrophages phagocytose asbestos fibers and coat them with ferritin

Question 11

hypersensiticity pneumonitis

Answer 11

inhaled Ag producing granulomatous interstitial pneumonitis (extrinsic allergic alveolits)

type 3 HS reaction: first exposure: Ig antibodies in surum, second exposure: Ab combine with inhaled Ag to form immune complexes–> inflammatory response in lung (interstitial )

Chronic: granuloma formation (type 4 hypersensitivity repsonse)

Farmers lung- moldy hay, thermophillic actinomyctes bacteria, silofillers disease, inhalation of gases from plant material, byssinosis, cotton linen hemp, textile factory workers, monday fever

Question 12

Sarcoidosis

Answer 12

Multisystem granulomatous disease of unknown etiology
Hughest in scandinavia

Disorder of immune regulation

Unknown Ag–> interaction with CD4 th cells–> cytokine release–> recruitment of monocytes/histiocytes–> non necrotizing granuloma formation diagnisis of exclusion
usually lung

Skin nodular granulomatous lesion, lupus
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